Multiple output stream particle beneficiation and chemical processing

ABSTRACT

A reactor ( 110 ) serves to combust residual carbon in fine particulate matter, remove a contaminant from fine particulate matter, or change the composition of fine particulate matter. The reactor output is processed by particle collection devices ( 115, 125, 140, 155, 175 ) and heat exchangers ( 135, 150, 165 ) to provide particle outputs ( 118, 124, 131, 144, 159 ) of different sizes. A contaminant, such as carbon or a metal, is combusted, vaporized, volatized, broken down, or substantially appears on one particle output ( 144 ) so that another particle output and the exhaust gas ( 142 ) are substantially contaminant-free. Different outputs can also be selectively mixed, as desired, to product a combined output ( 171 ). Fly ash and silica fume can be processed separately or together to reduce the amount of unburned carbon in both. Metals can also be removed from the fine particulate matter. Kaolin can also be processed to produce metakaolin.

PRIORITY CLAIM

This application claims the priority of U.S. Provisional PatentApplication Ser. No. 61/328,268, filed Apr. 27, 2010, entitled “MultipleOutput Stream Fly Ash Beneficiation Process”, and this application isalso a continuation-in-part of U.S. patent application Ser. No.11/424,364, filed Jun. 15, 2006, entitled “Method And Apparatus ForTurbulent Combustion Of Fly Ash”, which claims the priority of U.S.Provisional Patent Application Ser. No. 60/691,729, filed Jun. 17, 2005,entitled “Method And Apparatus For Turbulent Combustion Of Fly Ash”.

FIELD OF THE INVENTION

The present invention relates to the processing of fine particulatematter to modify its chemical and/or its physical characteristics,and/or modify the chemical and/or physical characteristics of acontaminant associated with the fine particulate matter for removal ofthe contaminant, for example, but not limited to, the combusting ofunburned carbon in fly ash or silica fume, the removal of metals, andthe conversion of kaolin to metakaolin.

BACKGROUND OF THE INVENTION

There are many by-products and natural products which have a valueand/or utility limited partly or largely by the contaminants includedtherein. The nature and amount of the contaminant can, in cases,eliminate all substantial uses of the product, which often results inthe product being transported to, and dumped in, a landfill.

For example, the positive economic and technical benefits of utilizingfly ash as a replacement for cement in concrete have been wellestablished. Further, it is well known that ever increasingenvironmental regulations on coal-fired plants has led to thedevelopment of several types of fly ash beneficiation processes designedto make a product suitable for utilization.

The greatest barrier to higher utilization rates for coal fly ash is theheterogeneous nature of fly ash itself. The single greatest cause ofheterogeneity within coal fly ash stems from residual unburned carbon,which remains in the fly ash in varying amounts—depending on theefficiency of the coal combustion process that produced the fly ash.These unburned carbon particles are typically agglomerations ofdevolatized coal char and partially vitrified inorganic inclusions.These tiny inorganic inclusions would have become separate, discrete flyash particles if the coal had been able to burn completely whenoriginally fired in the boiler.

Because coal fly ash is primarily inorganic mineral matter, thepreferred uses for fly ash intend to take advantage of the specificnature and characteristics of the mineral matter—e.g., reactive glass,spherical morphology, particle size distribution, etc. There aresignificant differences between the nature and character of the mineralmatter and the residual carbon in fly ash, and these differences affectthe performance of fly ash; particularly, the differences in density,color, surface chemistry, adsorption, etc.

Consequently, in some applications that may benefit from the uniquecharacter of the mineral matter in fly ash, the very presence of anyunburned carbon negatively affects the performance of the resultingproduct. This results in a reduction in the utilization rates of flyash. Additionally, due to differences in the combustion techniquesand/or efficiency of different coal-fired boilers and differences in thecomposition of the coal being burned, inconsistent amounts of unburnedcarbon in the raw fly ash product further limits the applications forthe fly ash and results in still lower utilization rates for fly ash.

There are other causes of heterogeneity in fly ash that are often citedas barriers to increased beneficial use of fly ash, especially when usedto produce non-cementious products, such as plastics, rubber, paints,adhesives, etc. Some of those causes are:

-   -   Contaminants (e.g., ammonia, activated carbon, etc.) introduced        through the combustion and pollution control processes and which        are collected in the fly ash;    -   Variable ash chemistry and color from coal switching/blending;    -   Agglomerates of mineral matter from high temperature and/or        fouling; and    -   Unburned organics and/or variable ash chemistry from co-firing        with alternative fuels, such as biomass and pet coke.

SUMMARY OF THE INVENTION

A reactor heats a feedstock in the form of particulate matter to alterthe chemical and/or physical nature of the feedstock or a contaminant inthe feedstock to remove the contaminant. Some examples are calcinationof certain materials, combusting unburned carbon from fly ash or silicafume, removing water, including crystalline water, from fly ash,conversion of kaolin to metakaolin, etc. Particle collection devices andheat exchangers then separate and cool the output from the reactor intomultiple particle outputs of different sizes. If the feedstock containsa contaminant, such as but not limited to selenium or an oxide ofselenium, then the contaminant can be removed from the feedstock andcaused to substantially appear on one of the particle outputs, withother particle outputs and exhaust gases being substantially free of thecontaminant, or to just substantially appear in the exhaust gas.Different input feedstocks can be co-processed, and different outputproducts can be selectively mixed, as desired, to produce a desired orcombined output. For example, silica fume can be co-processed with flyash to reduce the amount of unburned carbon in both the silica fume andthe fly ash, which can be provided as a combined product or as separateoutput products. In another example, kaolin can be co-processed with thefly ash to produce metakaolin, and the processed fly ash and themetakaolin can be provided as separate output products. Fly ash is aconvenient source of heat for the reactor, but is not the only possiblesource, as other fuels can be used. These examples illustrate that oneor more additional input feedstock(s) can be processed with or withoutfly ash to effect desired physical and/or chemical changes to the inputfeedstock(s) and/or contaminants therein. The input feedstock(s) arenot, however, limited to the above examples.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A and 1B show one exemplary embodiment of a system for processingparticulate matter using several particulate collection devices and aheat exchanger.

FIGS. 1A and 1C show another exemplary embodiment of a system forprocessing particulate matter using several particulate collectiondevices with two heat exchangers.

FIG. 2A illustrates one exemplary embodiment for the extraction ofprocessed particulate matter from various points within a reactor.

FIG. 2B illustrates another exemplary embodiment for the extraction ofprocessed particulate matter from various points within a reactor.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A-1C show two exemplary embodiments of a system for processingparticulate matter to produce at least two different output productstreams. FIGS. 1A and 1B show a system for processing particulate matterusing several particulate collection devices and an intermediate heatexchanger. FIGS. 1A and 1C show another system for processingparticulate matter using several particulate collection devices with twoheat exchangers.

FIG. 1A is common to both implementations and shows a reactor 110, aparticulate collection device (PCD) 115, and a solids return controldevice (SRCD) 120. For convenience of illustration and discussion,reactor 110 is shown as having three sections: a top section 110A, acentral section 110B, and a bottom section 110C. The sections need nothave similar volumes or dimensions.

The top section 110A, although shown generally as a dome, may be anothershape. For example, the top section 110A may be a simple flat lid whichseals the upper end of the central section 110B. Also, although the exit121 is shown as being at the top of the dome in top section 110A, exit121 may be at a different point on the dome of top section 110A, may beat a desired point on a differently-shaped top section 110A, or may evenbe near the upper end of the central section 110B. It is only importantthat there be an exit point somewhere near the upper end of the centralsection 110B.

The central section 110B is where most of the chemical reactions andphysical changes occur, although some reactions and changes may alsooccur in the top section 110A and in the bottom section 110C. Thecentral section 110B preferably has multiple input points (ports) 109,114, 117, and multiple output points (ports) 119. For convenience ofillustration, FIG. 1A shows a single conduit 108 feeding the variousinput ports 109. Valves (not shown) may be used to select which inputports are to be active. If desired, there may be a plurality (not shown)of conduits 108, each conduit 108 selectively feeding a different inputport (or ports) than other conduits 108. This allows differentfeedstocks or compositions, including but not limited to reagents andreactants, to be introduced at different input points so as to obtainthe desired output product or products.

Valves (not shown) may be used to select which input ports 114 are to beprovided secondary air via conduit 113. This provides for better controlof the operating conditions in the reactor 110. Further, these inputports 114 may also be used to introduce substances, including but notlimited to reagents and reactants, other than secondary air. If desired,there may be a plurality (not shown) of conduits 113, each conduit 113selectively feeding a different input port (or ports) than otherconduits 113. This allows different feedstocks or compositions to beintroduced at different input points so as to obtain the desired outputproduct or products.

Valves (not shown) may be used to select which input ports 117 are to beprovided cooling spray via conduit 116. This provides for better controlof the operating conditions in the reactor 110. Further, these inputports 117 may also be used to introduce substances, including but notlimited to reagents and reactants, other than cooling spray. If desired,there may be a plurality (not shown) of conduits 116, each conduit 116selectively feeding a different input port (or ports) than otherconduits 116. This allows cooling spray and/or other liquids to beintroduced at different input points so as to obtain the desired outputproduct or products.

An input port 109, 114, 117 may be a simple opening in the wall of thereactor 110, or may be a conduit protruding into the reactor 110, or maybe a nozzle. The use of a conduit or a nozzle (not shown) allows air,cooling spray, or an input feedstock, to be injected into the reactor ina desired orientation. For example, the material to be injected may beinjected radially inward, in the direction of (or against) the flowinside the reactor, and/or upwardly (or downwardly). The orientation ofinjection can be used to control, for example, the duration that aparticle will be inside the reactor and the degree to which thatparticle will be altered.

The bottom section 110C, although shown as a separate component, may bea continuation of the central section 110B with the walls of the centralsection 110B tapering inwardly downward a desired distance to provide adesired diameter at the bottom of section 110C. Although the bottomsection 110C is shown as having a flat bottom surface, it may haveanother desired shape, such as a cone or a bowl. Also, although theprimary air 112 is shown as being provided to the bottom section 110C,the primary air may be provided at an alternate or additional location,such as toward the lower end of central section 110B. Larger and/orcoarser particles are removed from the reactor 110 at or near the bottomsection 110C, such as via conduit 118. It is only important that therebe an input point somewhere near the lower end of the central section110B for the primary air input, and an exit point somewhere near thelower end of the central section 110B for removing the larger and/orcoarser particles.

For convenience of illustration, FIG. 1A shows a single conduit 112feeding the various primary air input ports. If desired, valves (notshown), may be used to select which input ports are to be active.Further, there may be a plurality (not shown) of conduits 112, eachconduit 112 selectively feeding different a input port (or ports) thanthe other conduits 112. An input port for the primary air may be asimple opening in the wall of the reactor 110, may be a conduitprotruding into the reactor 110, or may be a nozzle. These techniquesallow primary air to be injected into the reactor in a desiredorientation to control, for example, the duration that a particle willbe inside the reactor and the degree to which that particle will bealtered.

A PCD separate particulate matter in the input stream according to somepredetermined criteria, such as the size of the particles. Some examplesof PCDs are cyclones and baghouses. Some examples of SRCDs are J-valvesand L-valves. Other types of SRCDs may be used which can selectivelyenable or disable flow of the ash through the device, or route the ashto different outputs of the device.

The system described herein can be used for processing fine particulatematter. Fine particulate matter is finely divided material which can betransported pneumatically, which can be injected into the reactor, andmost of which can be upwardly buoyed by the air flow within the reactor.The fine particulate matter typically, but not necessarily, has a lowBTU value, meaning that it is not generally used as a fuel. It may evenbe the result of combusting a fuel, such as the fly ash produced bycombusting coal. Most of the particles in fine particulate matterpreferably, but not necessarily, have a size less than ⅜ inch and, evenmore preferably, will pass through a 16 mesh screen. Some examples offine particulate matter are ash and silica fume. Ash is the remainingmineral matter after a combustion process involving organic(carbon-containing) matter. Thus, the term ash includes, for example,fly ash and wood ash. Organic matter includes, for example, coal,hydrocarbons, and biomass, such as wood, switch grass, agricultural andresidential plant waste, etc. Many types of feedstock may be processed,singly or concurrently, in the system described below. For convenienceand clarity of discussion, however, the description herein primarilyfocuses on the processing of fly ash particles as the feedstock or feedash to remove or reduce residual carbon levels and/or other contaminantsin the feedstock fly ash particles.

Reactor 110 may be, and preferably is, preheated to the desiredoperating temperature by the injection of oil, gas, or other flammableliquid or vapor through any suitable port 109, 114, 117, or a differentport (not shown). The operating temperature should be high enough tomodify the contaminant so that it can be removed from the particulatematter. Removal of the contaminant may be accomplished by, for example,combusting the contaminant, vaporizing the contaminant, or volatizingthe contaminant.

After the reactor has reached the desired operating temperature then thereactor 110 is provided with feedstock ash via conduit 108 at thedesired levels or input ports 109, primary air via conduit 112,secondary air via conduit 113, and, optionally, cooling spray viaconduit 116 as needed. Primary air is injected at or near the bottom ofthe reactor 110. The secondary air is preferably injected into thereactor 110 at several levels 114A, 114B, 114C, and the amount of airinjected at each level is preferably independently controllable. Fly ashis preferably injected above the primary air injection level. Theprimary and secondary air promote the upward movement of the fly ashwithin the reactor 110 and facilitate beneficiation, that is, reductionor removal of unburned carbon in the fly ash. “Air” includes air, andalso may include oxygen, other gases, and mixtures thereof.

The cooling spray may be, and is preferably, injected into the reactor110 at several levels 117A, 117B, 117C, and the amount of water injectedat each level is preferably independently controllable to control theoperating temperature and conditions inside the reactor 110 and to causeor maintain the fly ash particles to be in finely divided state. Thecooling spray is preferably water. Cooling spray may also be injected,if desired, into conduits 122 (FIG. 1A), 126 (FIG. 1A), 133 (FIG. 1B),137 (FIG. 1B), 152 (FIG. 1C),157 (FIG. 1C), 162 (FIG. 1C), and/or otherpoints.

Typically, most of the coarser or larger fly ash particles will movetoward the bottom section 110C and can be removed via conduit 118 toprovide an output C of the reactor. Also, most of the fine fly ashparticles will typically exit with the flue gas at the exit 121. Theseare not required to be the only output points, however. The averageparticle size or degree of carbon reduction at any elevation or crosssection in the reactor may be different. Fly ash can thereforepreferably be removed from the reactor at multiple locations (FIGS. 2Aand 2B), either laterally or vertically, to obtain a product withspecific characteristics, such as particle size or carbon reduction.

The reactor 110 is preferably operated within a temperature range ofabout 1000 degrees F. to about 2200 degrees F., a gas residence time of3 to 20 sec, an oxygen concentration ranging between reducing conditionsto 20% excess O2, solids mass flux of 10 to 100 inches water gauge (wg),and recycle ratio of 10 to 1. These are preferred parameter ranges, butthe actual preferred ranges will vary, and operation outside of theseranges may occur in order to achieve a particular result orcharacteristics of the feedstock ash and/or the type of beneficiationdesired. For example, in order to produce a Class F fly ash product withvery little or no residual carbon, the preferred temperature range is1400 to 1800 degrees F. at a residence time of 6 to 12 sec and withexcess O2 of 2 to 10%. More preferably, the temperature range is 1500 to1700 degrees F. at a residence time of 8 to 10 sec and with excess O2 of3 to 8%. The actual operating temperature, oxygen level, and residencetime will depend upon the initial carbon level in the raw fly ash andthe desired carbon level in the processed fly ash.

The particles leaving the exit 121 are transported via a conduit 122 tothe input of a PCD 115. The PCD is operated within a temperature rangeof 1000 degrees F. to 2200 degrees F., an oxygen concentration rangingbetween reducing conditions to 20% excess O2, solids and gas pressuredifferential of 0 to 50 inches wg. The preferred ranges for theseparameters will vary based on the specific characteristics of thefeedstock ash and/or the type of beneficiation desired. For example, inorder to produce a Class F fly ash product with very little or noresidual carbon, the preferred temperature range is 1400 to 1800 degreesF., with excess O2 of 2 to 10%. More preferably, the temperature rangeis 1500 to 1700 degrees F., with excess O2 of 3 to 8%.

The larger of the fly ash particles entering the PCD 115 from the exit121 will fall to the bottom of the PCD 115 and exit the PCD 115 as aparticulate output 127 on conduit 128. These fly ash particles may thenbe directed by the SRCD 120 back into the reactor via conduit 123 or maybe transported via conduit 124 to provide an output B. The amount ofsolids returned to the reactor can be varied in order to control thereactor operating conditions to the desired level, such as temperatureor mass flux. For example, hot fly ash may be returned to add additionalhot mass to the inside of the reactor to enhance heating or stabilizethe temperature. Also, fly ash which has been cooled, such as by thecooling water spray, may be returned to add cooler mass to the inside ofthe reactor to reduce heating or stabilize the temperature. Theoperating temperature at the output of the SRCD 120 will be in the rangeof 1000 to 2200 degrees F., depending upon the operating conditions ofthe reactor 110 and the amount of cooling spray injected. The preferredoperating conditions are dependent on the specific output productdesired.

In another example, the SRCD 120 may be controlled to cause some, most,or all of the ash at the bottom of the PCD 115 to be redirected to thereactor 110 via conduit 123. Thus, some or all of the particlescollected by the PCD may make multiple passes through the reactor 110,thereby increasing the residence time of the particles in the reactor110, reducing the residual carbon levels in the particles, andinfluencing the operating conditions of the reactor such as temperatureor mass flux.

In another example, SRCD 120 may be controlled to cause little, or none,of the ash at the bottom of PCD 115 to be redirected to the reactor 110.Thus, most or all of the particles collected by the PCD 115 only makeone pass through the reactor 110.

The output 121 at the top of the PCD 115 is hot flue gas which containsthe combusted carbon and any contaminants, such vaporized or volatizedmetals, and fly ash particles which have not been removed by the PCD115, typically fine to ultra-fine fly ash particles. This output isprovided via conduit 126 to become output A. The operating temperatureat this point is 1000 to 2200 degrees F. and the oxygen concentrationranging between reducing conditions to 20% excess O2, depending upon theoperating conditions of the reactor 110 and the amount of cooling sprayinjected. The preferred operating conditions are dependent on thespecific product desired.

FIG. 1A also shows a plurality of outputs 119A-119N to extractbeneficiated fly ash from various locations within the reactor. For easeof illustration, conduits from these outputs 119 are not shown. Theseoutputs 119 may be routed directly to a desired process or collectionarea, may be routed to the mixer 130 in FIGS. 1B and 1C, may be directlycombined with other outputs, etc. Each output may be individuallycontrolled by use of, for example, an SRCD. Construction of theseoutputs 119 is described with respect to FIGS. 2A and 2B. Forconvenience of discussion, these outputs 119 are referred to as outputD.

Thus, there are multiple outputs from the reactor 110: output A is thehot flue gas which includes the combusted carbon, vaporized or volatizedmetals, and the fine to ultra-fine beneficiated fly ash particles,output B is the beneficiated medium-size fly ash particles extracted bythe PCD, output C is the beneficiated larger or coarser fly ashparticles, and output D is fly ash particles with selected chemicaland/or physical characteristics.

Preferably, the operating temperature inside the reactor, thetemperature of the hot flue gas and fly ash particles at the exit 121 ofthe reactor, and the temperature of the hot flue gas and fly ash at theoutput 129 of the PCD 115, are all above the vaporization point of anyelemental or volatized metals targeted for removal. For convenience ofdiscussion, both vaporized elemental metals and vaporized volatizedmetals will be referred to as “vaporized metals” unless stated otherwiseor unless required by the context in which the term is used. If thesetemperature conditions are met, the vaporized metals will remainentrained in the hot flue gas and will not condense on or attach to thefly ash particles. Output A will therefore contain hot flue gas,beneficiated fly ash not removed by the SRCD 115, and vaporized metals.As outputs B, C, and D contain fly ash particles which were removed fromthe flue gas while still above the vaporization point of the metals,there will be little or none of the metal on these beneficiated fly ashparticles.

The term “conduit” is not limiting as to size, shape or construction,and includes, for example, a tube, passage, channel, pipe, shaft, orduct, which allows or facilitates movement of fly ash, liquids, gases,particulate matter, and/or other materials from one place to another.Likewise, the term “output” is not limiting as to size or shape, andincludes, for example, a hole, port, bore, or open area, from whichmaterial, such as fly ash particles, may leave an object, such as areactor, PCD, or heat exchanger, and may also indicate, according to thecontext in which it is used, the material itself.

Tuning now to FIG. 1B, the output A goes into a second PCD 125. Some ofthe fine fly ash exits the output 134 at the bottom of the PCD 125 and,preferably but not necessarily, is provided via a conduit 131 to a mixer130. The temperature inside the second PCD 125 is also above thevaporization temperature of the targeted metals, so the output 132 ofPCD 125 contains the hot gas, the vaporized metals, and any fine orultra-fine residual fly ash particles, i.e., those fly ash particles notremoved by the PCDs 115 or 125.

The output 132 of PCD 125 is then provided via a conduit 133 to a heatexchanger 135, whereby the hot gases are cooled below the condensationtemperature of the targeted trace metal or metals. This cooling causesthe metal vapors to condense and adhere to the residual fly ashparticles. The output 136 of the heat exchanger 135 is then provided viaa conduit 137 to a PCD 140, which removes substantially all of theresidual fly ash particles, now metal-laden. The PCD 140 then provides asubstantially metal-reduced or metal-free exhaust gas output 141 via aconduit 142, and provides an output 143 of fly ash laden with targetedtrace metals via a conduit 144. The conditions at output 143 arepreferably a temperature in the range of 250 to 400 degrees F., with anoxygen concentration ranging of 2 to 20%. The preferred ranges for theseparameters will vary based on the specific characteristics of thefeedstock ash and/or the type of beneficiation desired.

Optionally, heat exchanger 135 will not cool the hot gases to thecondensation point of the vaporized metal. Therefore, the output 143will be fine fly ash with little or no metal, but the exhaust gas output141 will contain the vaporized metal, which can be removed by asubsequent process (not shown).

The PCDs 115 and 125, and the heat exchanger 135, may be considered tobe components of a particle collection and cooling section 160. Inanother embodiment, the particle collection and cooling section does notinclude PCD 115, so SRCD 120 is not used. The particles that would becollected by PCD 115 are, instead, collected by PCD 125. This may beacceptable if the output of PCD 125 is still appropriate for theparticular application. The elimination of PCD 115 and SRCD 120 is notpreferred, however, as these devices conveniently assist in maintainingthe reactor temperature at the desired level.

In another embodiment, the particle collection and cooling section doesnot include PCD 125, so the output on conduit 131 is not available. Theparticles that would be collected by PCD 125 are, instead, collected byPCD 115 or PCD 140, depending upon the particle size requirements of theparticular application.

In another embodiment, PCD 140 is not used. This may be acceptable ifthe output 136 of PCD 135 is appropriate for the particular application.

Turning now to FIG. 1C, the output A goes into a first heat exchanger150, which cools the temperature of the hot gas so that the hot gas canbe processed by a PCD 155, but the temperature of the hot gas is stillabove the vaporization point of the targeted trace metals. The output151 of the heat exchanger 150 is provided via a conduit 152 to the PCD155, which removes some of the fly ash particles. Because thetemperature is still above the vaporization temperature, the output 158of the PCD 155 is substantially metal reduced or metal free fine flyash. This output is provided via a conduit 159 to the mixer 130.

The other output 156 of the PCD 155 is slightly-cooled hot gas, whichstill contains vaporized metals and some fine and ultra-fine fly ashparticles. This output is provided via a conduit 157 to the second heatexchanger 165, whereby it is cooled below the condensation point of thetargeted metals. This cooling causes the metals to condense and adhereto the residual fly ash particles. The output 161 of the heat exchanger165 is then provided via a conduit 162 to another PCD 175, which removessubstantially all of the residual fly ash particles, now metal-laden.The PCD 175 then provides a substantially metal-reduced or metal-freeexhaust gas output 141 via a conduit 142, and provides an output 143 offly ash which is with laden with the trace metals via a conduit 144.

Optionally, heat exchanger 165 will not cool the hot gases to thecondensation point of the vaporized metal. Therefore, the output 143will be fine fly ash with little or no metal, but the exhaust gas output141 will contain the vaporized metal, which can be removed by asubsequent process (not shown).

The PCDs 115 and 155, and the heat exchangers 150 and 165, may beconsidered to be components of a particle collection and cooling section160. In another embodiment, the particle collection and cooling sectiondoes not include PCD 115, so SRCD 120 is not used. The particles thatwould be collected by PCD 115 are, instead, collected by PCD 155. Thismay be acceptable if the output of PCD 155 is still appropriate for theparticular application. The elimination of PCD 115 and SRCD 120 is notpreferred, however, as these devices conveniently assist in maintainingthe reactor temperature at the desired level.

In another embodiment, the particle collection and cooling section doesnot include PCD 155, so the output on conduit 159 is not available. Theparticles that would be collected by PCD 155 are, instead, collected byPCD 115 or PCD 175, depending upon the particle size requirements of theparticular application.

In another embodiment, the particle collection and cooling section doesnot include heat exchanger 150. This may be acceptable if the PCD 155can operate at the higher temperatures which will then be present.

In another embodiment, PCD 175 is not used. This may be acceptable ifthe output 161 of PCD 165 is appropriate for the particular application.

At this point it will be noted that both exemplary configurations, FIGS.1A and 1B, and FIGS. 1A and 1C, provide multiple output streams:substantially metal-free and fly ash-free exhaust gas via conduit 142,metal-laden fly ash via conduit 144, substantially metal-reduced ormetal-free beneficiated fly ash via conduit 131 or 159, substantiallymetal-reduced or metal-free medium-size beneficiated fly ash particlesvia conduit 124, substantially metal-reduced or metal-free beneficiatedfly ash with larger or coarser particles via conduit 118, andsubstantially metal-reduced or metal-free beneficiated fly ash withselected characteristics via output D. Note also that the carbon in thefly ash feedstock has also been substantially reduced or completelyremoved.

Thus, if selenium is the targeted metal, the process will simultaneouslyproduce at least one product stream with selenium levels below thedetection limit for most tests, and another product stream with elevatedlevels of selenium.

Typically, exhaust gas conduit 142 is connected to a vacuum source, suchas an induced draft fan or a flue gas treatment system, which pulls theexhaust gas out of the PCD 140 or 175.

It should be noted that, in operation, substantially all of theparticles in the reactor 110 are airborne, that is, the particles do notreside in a bed. Larger and coarser particles may drop out of theairflow but this is for removal via conduit 118 and not for forming abed.

The amount of contaminant in the particles, how much of the contaminantis to be removed, the size, density and weight of the particles, thedifficulty or ease with which the contaminant is removed, and thetemperature inside the reactor influence the rate of injection of air,oxygen, other gases, or mixtures thereof via the primary and secondaryair ports, and the number, location, and orientation of the injectiondevices. These parameters are easily determined by routineexperimentation by one of ordinary skill in the art who has had thebenefit of reading the present disclosure.

In one embodiment, these different output streams are maintainedseparate and are provided for further separate use.

In another embodiment, one or more of these streams may be combined toprovide a product with a desired mix of fine, medium and/or larger orcoarser fly ash particles. For example, in FIG. 1B, conduits 118, 124,and 131 are provided to a mixer 130, and in FIG. 1C, conduits 118, 124,and 159 are provided to a mixer 130. As mentioned, one or more of outputD may also be provided to mixer 130 but, for ease of illustration, isnot shown. These variously-sized fly ash particles may be combined inthe desired ratios to provide a desired product at the output 170 ofmixer 130, which may then be provided via conduit 171 to anotherprocess. Control valves (not shown) in the conduits 118, 124, 131, 159may be used to control the relative amount of each size fly ash particlein the output product. Thus, the output 170 may be selectively variedfrom being only one size fly ash (fine, medium, larger/coarser) to adesired ratio mixture of any two sizes, or even to a desired ratiomixture of three or more types or sizes. A carbon-containing fly ashparticle injected toward the lower part of the reactor 110 willtypically have lower and lower levels of residual carbon as it movesupward in the reactor 110. Therefore, the different outputs D can beused to provide different fly ash products with different levels ofresidual carbon. Note that the output 170 on conduit 171 issubstantially free of targeted trace metals.

FIGS. 2A and 2B illustrate two exemplary embodiments for the extractionof fly ash from within the reactor. In FIG. 2A a plurality of probes119E-119H, collectively designated as providing an output D, projectinto the reactor. As can be seen, probe 119E is turned downward so itcan extract beneficiated fly ash at a different level than the level atwhich it enters the reactor. Conversely, probe 119H is turned upward soit can extract beneficiated fly ash at a different level than the levelat which it enters the reactor. Probes 119F and 119G extract fly ash atthe same level at which they enter the reactor. Also note that, in theillustration as drawn, each probe is extracting fly ash at a differentpoint radially with respect to the center of the reactor. One could alsohave a plurality of probes around the reactor, all at the same level,but each projecting a different distance into the reactor. One couldalso have a plurality of probes around the reactor, all projecting thedistance into the reactor, but each being at a different level.

In FIG. 2B a plurality of probes 119J-119M project into the reactor 110.Probes 119J and 119L are projecting radially through the interior of thereactor, but probes 119K and 119M are projecting tangentially.

Thus, as shown in FIGS. 2A and 2B, it is possible to use the probes 119to extract beneficiated fly ash from any desired height within thereactor, and from any desired point at a desired height within thereactor. This allows selection, if desired, of fly ash with differentresidual carbon levels and different particle sizes.

Referring again to FIGS. 1A-1C, the system and process shown anddescribed can be used to control desired characteristics of the variousparticulate output streams by controlling the temperature of the reactor110 and/or the amount of re-injected ash, primary air, secondary air,and/or cooling spray provided. The residual carbon in the resulting flyash particles may also be controlled by adjusting the amount ordistribution of primary and/or secondary air, and or the temperature,such as by controlling the cooling spray, or by the feedstockdistribution, or by the solids reinjection rate, or by the mass flux inthe reactor. For example, if it is desired that the output C have moreresidual carbon, then the amount of primary air provided and/or theamount of secondary air provided to the reactor 110 may be adjusted toinfluence the stoichiometric conditions of either the lower or upperpart of the reactor.

Typical ranges for feedstock ash are from 5% to 20% Loss On Ignition(LOI), and typical ranges for the output fly ash particles are from 0.1%to 5% LOI.

The part of the processed fly ash which is metal laden can be used inproducts, such as concrete, that do not restrict the presence of thesecontaminants and which will serve to reduce their potential toxicityand/or sequester them, as in the case of selenium, for example, throughentombment in the cementious paste matrix of concrete products.

Processing fly ash as described herein provides multiple separatestreams of differently-sized fly ash. The process can be operated insuch as way as to size-classify the product fly ash, modifying theparticle size distribution and tailoring it to the expectations and/orrequirements of particular markets, such as high-value mineral fillersfor plastics and paints. A typical, although not an exclusive, use ofthe larger/coarser fly ash particles that are substantially free oftrace metals is as functional fillers in rubbers and plastics. Atypical, although not an exclusive, use of the medium-sized fly ashparticles that are substantially free of trace metals is as functionalfillers in paints and plastics. A typical, although not an exclusive,use of the fine fly ash particles that are substantially free of tracemetals is as functional fillers in paints and other coatings.

In addition to removing trace metals and carbon, it should be noted thatthis process can also be used to reduce or remove many othercontaminants, further enhancing its value in certain consumer productsand some manufacturing processes, especially high-temperature processes.The process can also capture these contaminants and sequester them inbeneficiated fly ash.

Although the above embodiments particularly discuss the handling oftargeted trace metals and other contaminants so as to cause thesecontaminants to be present in only one of the outputs, the invention isnot so limited. Rather, within the temperature limits imposed by thephysical limitations of the PCDs and heat exchangers, this invention maybe used to cause other contaminants or undesired chemicals to be reducedin some fly ash output products and concentrated in other fly ash outputproduct(s) by selecting when the temperature is to be reduced, and byhow much the temperature is to be reduced. For example, if there are twocontaminants, contaminant A having a vaporization point of 2100 degreesF., and contaminant B having a vaporization point of 1900 degrees F.,then cooling the flue gas to, for example, 2000 degrees F. will causecontaminant A to condense on the fly ash particles. Contaminant B wouldremain in the flue gas and could then be removed by another process.

The process described herein is preferably operated as a continuousprocess.

Residual unburned carbon contained in by-product fly ashes can bepartially reduced, to a desired level, or can be totally removed fromthe fly ash, thereby resulting in a purified mineral matter.

Particles of “carbon char”, which in effect are agglomerates of coalcoke and inclusions of inorganic mineral matter, can be volatized,leaving only the former inclusions of mineral matter, while vaporizinginorganic matter, such as alkali salts, that condensed on inorganic ashparticles during initial coal-firing and that functions as a “fouling”glue to agglomerate inorganic ash particles.

Consequently, the processed fly ashes are fine, and the StrengthActivity Index (SAI) of the processed fly ash is higher than the normfor other Class F fly ashes in the marketplace and are higher thantypical SAI values for low-calcium fly ash. The SAI of the processed flyash can therefore be increased by processing the fly ash as describedherein.

The amount of trace metals or other contaminants on the product can becontrolled or eliminated by altering the operating conditions at variouslocations in the process, thus allowing for a purified mineral matter.

The process operates at temperatures that are high enough to burn offresidual organics comingled in the fly ash, including coal charparticles and other unburned organics from alternative fuels.

Oxidizing the residual unburned carbon in the raw fly ash improves theair-entraining characteristics of the processed fly ash used in theproduction of concrete. Oxidized unburned carbon adsorbs less of thechemical air-entraining agents (AEAs) used to produce concrete. This“oxidizing treatment” for unburned carbon will change the surfacechemistry of the carbon, increasing its polarity. This process issometimes referred to as carbon “passivation”. The polarity of themineral matter and residual carbon can be changed so as to decrease theamount of active surface sites in the processed fly ash or to leave aportion of the active surface sites intact or to increase the amount ofactive surface sites by processing fly ash in a reducing atmosphere.Therefore, in this example, a fly ash product can be produced with AEAcharacteristics which match other supplementary cementious materialsthat are used in a particular concrete.

If desired, only a portion of the organic carbon may be burned,especially the partially burned/coked carbon from the reactive coalmacerals, while still oxidizing the active surface sites on theremaining organic carbon without volatizing it. In addition, raw fly ashmay also contain inorganic carbon, such as carbonates. This inorganiccarbon is not highly adsorptive and, therefore, does not negativelyimpact the concrete air-entraining characteristics of the fly ash. Thisinorganic carbon can, however, be volatized along with the organiccarbon, thereby increasing the polarity of the processed fly ash. Forexample, the LOI of the processed fly ash can be reduced to below 0.5%,and even further, but then the organic carbon content is below theminimum detection limit of most common tests. This effect is highlyadvantageous when the product is used in water-based substrates, such ashydraulic cementious concrete, because the increased polarity of theproducts “wets” more efficiently and, therefore, requires less water toattain the desired viscosity (e.g., slump). Preferably, however, theorganic carbon and some of the inorganic carbon are volatized, but notall of the inorganic carbon is volatized, thereby minimizing carbonemissions from the process.

Fly ash mineral matter is, by its nature, mostly polar. Therefore,increasing the polarity of any unburned carbon remaining in fly ashreduces one major cause of heterogeneity in fly ash. Of course, therewill still be several other differences between the remaining unburnedcarbon and the mineral matter, such as particle density and color.Increasing the polarity of unburned carbon, however, will allow flyashes containing some unburned carbon to be used in a number ofmanufacturing processes that would not otherwise be able to use fly ash.

For example, the adsorptive nature of unburned carbon in fly ash hasbeen a major barrier for entry into a number of high-value, mineralfiller markets. Oxidizing treatment of residual unburned carbon in flyash allows these fly ashes to be more easily compounded and reducestheir affinity to adsorb expensive chemicals with polar endpoints orsmall polar particles, such as water.

Color also affects the market for some products. In some cases, theprocessed fly ash has little or no carbon but has a slightly tan color.It is believed that is due to at least some of the included iron beingoxidized to change from magnetite, which is black, to hematite, which isred.

The benefits provided by the present invention are not limited toreducing residual carbon levels in fly ash. The finely-divided nature ofthe processed fly ash results in improvements in the strength ofconcrete made using the processed fly ash. This benefit also appearswhen a high calcium (approximately 25% CaO) fly ash was processed; theconcrete made with the processed fly ash was stronger than theunprocessed fly ash. Further, Class F fly ash and Class C fly ash wereblended and processed to provide a Class F fly ash with thestrength-producing characteristics of Class C fly ash.

A typical large char particle (approximately 100 microns) containshundreds of small ash particles, ranging in size from 30 microns tosub-micron size. A typical smaller char particle (approximately 35microns) also contains a number of small ash particles, ranging from 5microns to sub-micron size. Processing as described herein combusts thecarbon, thereby freeing these small ash particles from the char particleand increasing the amount of extremely fine ash particles in theprocessed fly ash as compared to the original, unprocessed fly ash.

A type of agglomerate that can be found in coal fly ash results from“ash fouling” and subsequent soot-blowing activities that take place inmost coal-fired boiler operations. Ash fouling happens as hot flue gasesare cooled in coal-fired boilers, especially on or near the water wallsand boiler tubes. Vaporized inorganics, especially alkaline earthmetals, condense on these cooler surfaces, act as a “sticky glue”, andcapture many individual ash particles, thereby creating a build-up onthe cooler surfaces of the boiler. As the build-up increases, sootblowing and other cleaning methods are used to dislodge these depositsfrom the walls and tubes of the boiler. Some of the dislodged depositssurvive as “fouled agglomerates” and are collected with the fly ash. Thefouled agglomerates which are often found in the by-product fly ashesare typically held together by this “glue” of alkaline earth metals.Processing as described herein reduces the quantity of this type ofagglomerate to negligible levels, further increases the fineness of thefly ash, and improves the spherical morphology of the particles. Theseeffects increase the yield of ultra-fine fly ash and improve the yieldand particle quality (sphericity) of the mineral matter when used asfunctional filler to make composites via extrusions and injectionmolding.

In addition to carbon and selenium, raw fly ash may also contain sulfurand variety of trace metals, such as aluminum, arsenic, barium,beryllium, cadmium, calcium, chromium, cobalt, copper, iron, lead,magnesium, manganese, mercury, nickel, polonium, silver, sodium,titanium, vanadium, and zinc. Although the concentration of most ofthese elements is fairly low, some markets are very intolerant ofcertain elements, and the amount of attention given to some of thesecontaminants is significant. For example, mercury is listed by the EPAas a “persistent bio-accumulative toxic chemical,” which means that itis not only toxic, but, because it cannot decompose to become lesstoxic, it persists in the environment and eventually bio-accumulates inthe food chain.

The term “contaminant”, as used herein, includes any substance whichdevalues or limits the use of a raw material and the removal of thatcontaminant is often referred to as beneficiation or remediation of theraw material. Removal of a contaminant may be accomplished, as describedherein, by combusting the contaminant, by vaporizing or volatizing thecontaminant so that the material can be extracted while the vaporized orvolatized contaminant is still vaporized, or by vaporizing or volatizingthe contaminant so that the material can be extracted while thecontaminant is vaporized and then recapturing the vaporized or volatizedcontaminant.

For example, the elements and chemicals mentioned above, as well asammonia, nitrites, nitrates, sulfites, sulfates, metals, etc., may beconsidered to be contaminants in certain products. In addition,depending upon the feedstock involved and the purification desired,carbon in certain forms or even in any form may be considered to be acontaminant, such as activated carbon, unburned or partially burnedorganics or biomass, coal char, hydrocarbons, etc. It should also benoted that an element or compound may be considered to be a contaminantin one product, but is desirable or at least not undesirable in anotherproduct. For example, the presence of a heavy metal in any detectableamount is generally considered to be undesirable in any applicationwhere children are involved as children often lick or even eat thingswhich an adult would not. In concrete, however, the presence of a heavymetal is generally not considered to be a problem. Even water may beconsidered to be contaminant. For example, fly ash has often been storedin landfills, where it eventually becomes wet. Wet fly ash isundesirable in most, if not all, concrete applications because the watercontent is variable and can adversely affect the strength and/or curingtime of the concrete. Thus, water is a contaminant when it is presentwith fly ash.

Generally speaking, when coal is fired in a boiler, some metalscontained in the coal are vaporized or volatilized and travel in the hotflue gases along with the fly ash. Depending on how these metalsspeciate, and the temperatures involved, a portion of them may adsorbonto the fly ash. Therefore, the amount of trace metals on thebeneficiated fly ash can vary according to where the ash is removed fromthe process. For example, the selenium content in the processed fly ashtaken from two different locations may vary by nearly two orders ofmagnitude. The particular operating temperatures required to vaporize,volatize and/or condense these trace metals on fly ash, as well as thespecific amount metals captured on fly ash, will vary depending on theparticular metal, type of coal, and how the metal speciates. Processingas described herein, along with appropriate selection of the operatingtemperatures and cooling, can result in a contaminant being depositedonly on the processed fine fly ash, thereby rendering the larger fly ashparticles to be substantially or completely free of that contaminant.

Processing as described herein will cause the vaporization of certainmetals that were captured with the fly ash. Most of these metals arealready oxidized and processing the fly ash as described herein willonly further increase the level of metal oxidation. Oxidized metals aregenerally much easier to capture through adsorption than non-oxidizedmetals and, therefore, trace metals adsorbed on the fly ash stays withthe fly ash when it is separated from the flue gas stream by the plant'sparticulate collection equipment. As the vaporized metals and fly ashare transported by the hot flue gases through the heat exchangers, theflow is cooled to temperatures below the condensation temperature of thevaporized or volatized metals so the vast majority of the vaporizedmetals condenses on the fine fly ash and is collected along with theprocessed fine fly ash.

In addition to the processing of fly ash, the apparatus described abovecan be used for the processing of silica fume, which is the smokebyproduct of producing silicon metal or ferrosilicon alloys. Silica fumeconsists primarily of amorphous (non-crystalline) silicon dioxide(SiO2). The silica fume contains very fine silica particulate matter,which is desirable in some applications, such as for cement inaccordance with ASTMC 1240, but the particulate matter also containsunburned carbon, which is undesirable. The individual particles areextremely small, approximately 1/100th the size of an average cementparticle. Because of its fine particles, large surface area, and thehigh SiO2 content, silica fume is a very reactive pozzolan when used inconcrete. Concrete containing silica fume can have very high strengthand can be very durable.

If the silica fume has a sufficiently high carbon content then it can beprocessed by itself in the same manner as the fly ash is processed. If,however, the carbon content of the silica fume is not adequate tomaintain the necessary temperature in the reactor then heat can be addedby combusting fuel, such as is done to initially heat the reactor. This,however, raises the expense of operation. Preferably, if the carboncontent of the silica fume is too low, then the silica fume and fly ashare processed simultaneously in the reactor, with the fly ash providingthe additional heat necessary to maintain the appropriate temperaturefor burning the carbon out of the silica fume. The comingledbeneficiated silica fume and beneficiated fly ash can be used, forexample, in concrete.

The beneficiated silica fume and beneficiated fly ash can also beseparated and used separately in different concrete applications. Silicafume particles are extremely small, with more than 95% of the particlesbeing less than 1 micrometer. The particle size of beneficiated fly ashparticles ranges from sub-micron to above 100 micrometers. Most of thebeneficiated fly ash particles, however, are larger than 1 micrometer.Therefore, particle size is a convenient manner of separating thebeneficiated silica fume from the beneficiated fly ash. For example,outputs B and C (FIG. 1), output 131 (FIG. 1B), and output 159 (FIG. 1C)can provide beneficiated fly ash, while output 141 (FIGS. 1B and 1C) canprovide beneficiated silica fume which is metal-laden.

Optionally, heat exchangers 135 (FIG. 1B) and 165 (FIG. 1C) will notcool the hot gases to the condensation point of the vaporized metal.Therefore, the output 143 (FIGS. 1B and 1C) will be silica fume withlittle or no the metal, but the exhaust gas output 141 will contain thevaporized metal, which can be removed by a subsequent process (notshown).

In addition to the carbon reduction, metal-capture, and other benefitsdescribed above, the apparatus described above can be used for theprocessing of other particulate matter to modify its physical andchemical characteristics. The reactor 110, with input and output portsindicated thereupon, provides a high-temperature, dynamic reactionchamber having controllable operating conditions. The beneficiation ofthe fly ash typically produces heat energy in excess of what is requiredto maintain the reactor at the desired temperature. Therefore, theexcess heat may be captured, for example, in the exhaust gas output atconduit 142, to provide energy for another process. This same energy canalso be used to process other materials in the reactor 110, especiallythose wherein an endothermic reaction occurs. Furthermore, the fly ashis mostly inert material, and generally will not chemically reactdirectly with other substances which are injected into the reactor 110.The carbon in the fly ash, although capable of being in chemicalreactions with substances which are injected into the reactor, isgenerally combusted and not available for reactions. The beneficiatedfly ash and the processed material can be separated in any appropriatemanner but a convenient method of separation is by particle size.

For example, metakaolin clay is very desirable for use in concrete. Likeother pozzolans (fly ash and silica fume are two common pozzolans),metakaolin reacts with the calcium hydroxide (lime) byproducts producedduring cement hydration. In this use, metakaolin boosts the compressivestrength, makes finishing easier, reduces efflorescence, mitigatesalkali-silica reaction, and maintains color, especially in whiteconcrete. Metakaolin is refined kaolin clay that is fired (calcined)under carefully controlled conditions to create an amorphousaluminosilicate that is reactive in concrete. Kaolin is transformed intometakaolin by the controlled application of heat (temperature ofapproximately 750 degrees C., 1382 degrees F.) which releases waterfrom, and changes the chemical composition of, the Kaolin throughdehydroxilization. With reference to FIGS. 1A-1C, the reactor 110 isheated to approximately this temperature, and then the fly ash andkaolin are introduced. The beneficiation of the fly ash provides theheat needed for the calcination of the kaolin to produce metakaolin. Theparticle size of metakaolin is less than the average particle size offly ash: 80% of the metakaolin particles have a size less than 2micrometers. Therefore, particle size is a convenient manner ofseparating the metakaolin from the beneficiated fly ash. For example,outputs B and C (FIG. 1), output 131 (FIG. 1B), and output 159 (FIG. 1C)can provide beneficiated fly ash, while output 141 (FIGS. 1B and 1C) canprovide metakaolin which is metal-laden.

In addition to kaolin, other materials can also be calcined including,but not limited to, calcination of Bayer gibbsite to produce alumina and“red mud”, and calcination of bauxite to remove crystalline water. Thered mud can then be processed later to separate the heavy metals.

Optionally, heat exchangers 135 (FIG. 1B) and 165 (FIG. 1C) will notcool the hot gases to the condensation point of the vaporized metal.Therefore, the output 143 (FIGS. 1B and 1C) will be metakaolin withlittle or no metal, but the exhaust gas output 141 will contain thevaporized metal, which can be removed by a subsequent process (notshown).

Another example of use is the processing of tar sands. Tar sands (alsosometimes referred to as oil sands) are a combination of clay, sand,water, and bitumen (a heavy black viscous oil). Tar sands can be minedand processed to extract the bitumen, which is then refined into oil.The processed sands are then typically returned to the pit or area fromwhich they were mined. The extraction process is not, however, 100%efficient, so some of the bitumen remains. In addition to losing thevalue of the bitumen which is not extracted, the remaining bitumen isnow considered by some authorities to be an environmental contaminantand returning the processed sands, with the remaining bitumen, to thepit or area from which they were mined is prohibited. Thus, theprocessed tar sands must then be cleaned or transported to an approveddumping site, which increases the cost of the mining and extractingoperations. The processed tar sands can, however, be further processedby the system described herein. The processed tar sands are injectedinto the reactor 110, whereby the remaining bitumen, any remainingwater, and any chemicals used to extract the bitumen from the sands, arecombusted or removed from the tar sands. The resulting tar sands arefree of bitumen and other contaminants, and can then be returned to thepit or area from which they were extracted, or can then be used foranother purpose.

Although operation has been described with particularity with respect tothe use of fly ash, the present invention is not so limited. Any fineparticulate matter can be injected into the reactor, such as, but notlimited to, unburned or partially burned biomass, wood ash, switchgrass, hog manure, chicken litter, etc. If the feedstock has a caloricvalue that will provide sufficient heat from combustion to obtain thedesired reactor temperature then that feedstock may be used by itself.If the caloric value is inadequate then additional heat may be added bythe burning of fuel, which may be injected by using, for example, one ormore of the ports 119, or by the addition of another feedstock whichprovides the required additional caloric value.

The method and apparatus described herein may therefore be used toremove a contaminant from a fine particulate matter feedstock, or toconvert the fine particulate matter feedstock to a different product.Other benefits of, and variations of, the method and apparatus describedherein may suggest themselves based on a reading of this application.

The invention claimed is:
 1. An apparatus, comprising: a single, dilute solids phase reactor having a top, a central section, and a bottom section with an exit port, and a top particle output port, the top particle output port being located on or near the top to provide for removal of exhaust gas and particles from the reactor, and the port being located on or near the bottom for removal of particles other than those particles passing through said top particle output port; a plurality of particle injection devices and a plurality of air injection devices situated at a plurality of heights on the reactor and arranged so fine particulate matter is injected into the reactor at a height above an adjacent air injection device, the fine particulate matter having a contaminant other than residual carbon; a particle collection and cooling section (115) to separate the exhaust gas and particles from the top particle output port of the reactor, and comprising a primary particle collection device comprising a heat exchanger operating in a preselected temperature range, and a particle exit port to remove a portion of the particles which are substantially absent said contaminant, within said preselected temperature range, and an exit port (126) to convey cooled particles to a final particle collection device comprising a heat exchanger, whereby the cooled particles collected in said final particle collection device contain said contaminant.
 2. The apparatus of claim 1 wherein the particle collection and cooling section comprises: a first heat exchanger to cool the exhaust gas and particles from the exit port of the reactor into a cooled exhaust gas; primary particle collection device to separate the cooled exhaust gas from the first heat exchanger into a first output and the second particle output based upon the first predetermined factor; a second heat exchanger to cool the first output of the primary particle collection device to not more than a predetermined temperature to provide the cooled output to the final particle collection device.
 3. The apparatus of claim 1 wherein the particle collection and cooling section comprises: a primary particle collection device to separate the exhaust gas and particles from the exit port of the reactor into a first output and the second particle output based upon the first predetermined factor; an intermediate particle collection device to separate the first output from the primary particle collection device into a first output and a fourth particle output based upon a third predetermined factor; a heat exchanger to cool the output of the intermediate particle collection device to not more than a predetermined temperature to provide the cooled output to the final particle collection device.
 4. The apparatus of claim 1 wherein the factors are predetermined particle sizes.
 5. The apparatus of claim 1 further comprising an output selector to selectively combine any of the particle outputs.
 6. The apparatus of claim 2 further comprising an output selector to selectively combine the first and second particle outputs to provide a combined output.
 7. The apparatus of claim 2 further comprising an output selector to selectively combine the first and second particle outputs to provide a combined output.
 8. The apparatus of claim 2 further comprising an output selector to selectively combine at least two of the particle outputs to provide a combined output.
 9. The apparatus of claim 1 further comprising a solids return control valve to divert a selected portion of the second particle output of the particle collection and cooling section to at least one of the injection devices.
 10. The apparatus of claim 1 wherein at least one of the injection devices is a secondary air injection.
 11. The apparatus of claim 1 wherein at least one of the plurality of injection devices is a liquid spray injection device situated on the central portion of the reactor.
 12. The apparatus of claim 1 wherein the temperature inside the reactor is above the condensation temperature of the contaminant, the particle collection and cooling section comprises a primary particle collection device to provide the second particle output and, in series, a subsequent heat exchanger to provide the cooled output, the temperature inside the primary particle collection device is above the condensation temperature of the contaminant, the temperature of the cooled output is below the vaporization temperature of the contaminant, and the temperature inside the final particle collection device is below the vaporization temperature of the contaminant, whereby the particles from the first and second particle output ports and the exhaust gas output of the final particle collection device are substantially free of the contaminant, and the third particle output of the final particle collection device has most of the contaminant.
 13. The apparatus of claim 1, wherein the temperature inside the reactor is sufficient to modify the composition of the fine particulate matter, and the third particle output of the final particle collection device includes the modified composition.
 14. The apparatus of claim 1, wherein the fine particulate matter is one of fly ash or silica fume, the fine particulate matter has at least some unburned carbon, the temperature inside the reactor is sufficient to reduce the level of unburned carbon, and the third particle output of the final particle collection device includes the reduced-carbon fly ash or silica fume.
 15. The apparatus of claim 1, wherein the fine particulate matter is fly ash, and at feast one of the injection devices is to inject silica fume into the reactor, both the fly ash and the silica fume having at least some unburned carbon, the temperature inside the reactor is sufficient to reduce the level of unburned carbon in both the fly ash and the silica fume, at least one of the first particle output and the second particle output includes the reduced-carbon fly ash, and the third particle output of the final particle collection device includes the reduced-carbon silica fume.
 16. The apparatus of claim 1, wherein the fine particulate matter is fly ash, and at least one of the injection devices is to inject kaolin into the reactor, the temperature inside the reactor is sufficient to convert the kaolin into metakaolin, and the third particle output of the final particle collection device includes the metakaolin.
 17. The apparatus of claim 1, and further comprising at least one intermediate output port on the central section of the reactor to provide an intermediate particle output, the intermediate output port being located below the exit port and above the first particle output port.
 18. The apparatus of claim 1, and further comprising a plurality of intermediate output ports (119) on the central section of the reactor to provide a corresponding plurality of intermediate particle outputs, a first of said intermediate particle output providing particles from a first location within the reactor, a second of said intermediate particle output providing particles from a second location within the reactor, the second location being different from the first location in at least one aspect.
 19. The apparatus of claim 18 wherein the at least one aspect is one of the height within the reactor, the radial distance from the center of the reactor, and, if an intermediate output port has a probe protruding into the reactor, the direction in which the probe was pointing.
 20. A method, comprising: injecting fine particles through at least one of a feed port (109 A-D) into a reactor, said fine particles containing a contaminant other than residual carbon; providing a reactor temperature sufficient to modify the physical state of the contaminant; removing exhaust gas and particles on or near the top (122) of the reactor; removing particles on or near the bottom of the reactor; in a solids separation device (115), removing particles conveyed from on or near the top (122) based upon a first predetermined factor (127); conveying the exhaust gas (A) and particles passed through (126) to a further solids separating device (125) and removing particles (133) based on a second predetermined factor (134) and conveying the exhaust gas and particles (133) to another solids separation device (135); and cooling the exhaust gas and the particles in device (135) to not more than a predetermined temperature and conveying particles (137) at said predetermined temperature to a further solids separating device (140); whereby the level of contaminant associated with particles (122, 133) is less than the level of contaminant contained in particles (137) entering the further separating device (140).
 21. The method of claim 20 wherein, after separating particles based upon the first predetermined factor and before cooling the exhaust gas and the particles (127), further comprising the step of: separating, based upon a further predetermined factor, the exhaust gas and particles into (a) particles (133) and (b) the exhaust gas.
 22. The method of claim 20 wherein the first and second predetermined factors are predetermined particle sizes.
 23. The method of claim 20 further comprising diverting a selected portion of the particles (134) into the reactor.
 24. The method of claim 20 wherein the temperature inside the reactor is above the condensation point of the contaminant, the temperature of the exhaust gas with the particles (122) contained therein is above the condensation point of the contaminant, the temperature of the exhaust gas with the particles (134) contained therein is above the condensation point of the contaminant, and the temperature of the cooled exhaust gas with the particles contained therein is below the vaporization point of the contaminant, whereby the particles (122, 127, 134) and the exhaust gas output are substantially free of the contaminant, and the particles have most of the contaminant.
 25. The method of claim 20 wherein the fine particulate matter is one of fly ash or silica fume, the fine particulate matter having at least some unburned carbon, the temperature inside the reactor is sufficient to reduce the level of unburned carbon in the fine particulate matter, and the particles of the fifth type include the reduced-carbon fly ash or silica fume.
 26. The method of claim 20 wherein the fine particulate matter is fly ash having unburned carbon, and further comprising injecting silica fume into the reactor, the silica fume having at least some unburned carbon, the temperature inside the reactor is sufficient to reduce the level of unburned carbon in both the fly ash and the silica fume.
 27. The method of claim 20 further comprising also injecting kaolin into the reactor, the temperature inside the reactor being sufficient to convert the kaolin into metakaolin.
 28. The method of claim 20 and further comprising removing intermediate particles at points between the plurality of said particle and air injecting devices.
 29. The method of claim 20 wherein the at least one aspect is one of the height within the reactor, the radial distance from the center of the reactor, and, if the intermediate particles are removed by a probe protruding into the reactor, the direction in which the probe was pointing. 